Steam generator



J. W. WALLIN STEAM GENERATOR Nov. 29, 1949 s sheets-sheet 2 Filed Sept. 26, 1944 I INVENTQR Jos-PH M /l/ALL/N.

' ATTORNEYS J. W. WALLIN STEAM GENERATOR Nov. 29, 1949 y3 Sheets-Sheet 3 Filed Sept. 26, 1944 Patented Nov. 29, 1949 STEAM GENERATOR Joseph W. Wallin, Williamsport, Pa., assgnor to E. Keeler Company, Williamsport, Pa., a corporation of Pennsylvania Application September 26, 1944, Serial No. 555,771

2 Claims. (Cl. 122-347) 1 This` invention relates to improvements in steam generators of the type set forth in United Statesy Patent No. 2,097,268, granted to Simon C. Best on October 26, 1937.

The primary object of this invention resides in a steam generator embodying the broad principles of steam generators set forth in the aforesaid patent in which two connected steam generating units are arranged in a single setting and fir-ed by a single furnace. By such an arrangement, it is possible to provide a relatively large steam generating unit over a single furnace in a minimum space and obtain a greater Water storage and steam liberating area.

Another important feature of the invention is to provide a twin unit steam generator in which the units are interconnected in a novel manner for operation as a single steam generator having a common water level.

A further feature of the invention is the provision of a steam generator embodying twin steam generating units superimposed over a furnace or combustion chamber, the whole or part of which is enclosed in a single setting constructed of either' all refractory material, or a combination of refractory material, insulating material, and an. outer steel jacket or casing, the refractory materials. being partially protected from the heat generated in the furnace or combustion chamber by water wall tubes which constitute an adjunct of the pressure unit.

A further feature of the invention is to provide a twin-unit steam generator which may be installed rover a furnace in which either oil, coal, wood, bagasse or other fuel may be used with such modification in the design of the furnace as may be necessary for the various types of fuel burning equipment required for burning the aforementioned fuels.

A still further feature of the invention is the provision of a twin-unit steam generator in which parts of the same are arranged in a novel manner to produce a single compact steam generator uni-t requiring a minimum amount of installation space, and capable of being economically operated at very high rates of combustion and steam generations without frequent and costly repairs.

Other novel features of the invention will become apparent as the following specification is read inconjunction with the accompanying drawings, in which,

Figure l is vertical longitudinal sectional View taken through one of the units of the twin-unit generator, certain parts being illustrated in elevation.

Figure 2 is a vertical transverse sectional View onthe line 2-2 of Figure 1.

Figure 3 is an enlarged vertical sectional view on the line 3 3 of Figure 1.

Referring to the drawings by reference characters, the numeral I designates the twin-unit steam generator in its entirety which broadly includes a pair of side-by-side steamv generator units A and B, a forward single furnace or combustion chamber C which is common to both units A and B and a single setting D which encloses the units A and B and chamber C. The setting D includes a front wall II, opposed rear wall I2, opposed side walls I3-I3, and a roof or top wall I4.

A refractory bridge wall I5 forms the rear wall of the furnace C. said bridge wall rising vertically within the setting and extending transversely thereof. The top of the bridge wall terminates short of the roof I4 to provide a communicating passage I 6 between the upper portion of the furnace C and the rear gas flow compartment I1 which constitutes that area within the setting which is rearward of the bridge wall I5. A gas and smoke outlet I8 is provided in the rear wall I2.

The furnace C may be fired by either cil, coal, wood, bagasse or other fuel. In the drawings I have shown for illustrative purposes. a coal burning installation known as a multiple retort rear dump type of stoker E. Coal to be burned by this type of stoker is fed to a hopper F at the front of the setting, from which it discharges onto the stoker grate surface G which has a series of retorts, at the bottom of each of which there is a pusher bar which oscillates back and forth causing the fuel to move and burn progressively toward the rear of the grate, combustion thereof being completed bv the time the rear of the furnace has been reached and where the ashes drop off into a chamber H. The heat from the burning fuel together with the hot gases and smoke therefrom rises in the furnace C, sweeps over the tcp of the bridge wall' I5 and travels in an undulated passage to the gas and smoke outlet I8 as indicated by the arrows in Figure 1. The bottom of the gas iiow compartment I1 is provided with soot-hoppers K into which soot drops during travel of the hot gases and smoke through said compartment. The discharge end of each soot-hopper is normally closed by a soot gate L which may be opened when the soot collected in the hopper is to be emptied therefrom. It will be understood that when fuel other than coal fed to the furnace by stoker is used, the

design of the furnace may be changed accordingly, but in al1 instances the furnace or combustion chamber C extends the full width of the setting D at the front thereof.

The twin-steam generating units A and B are identical in construction, therefore a description of one will suffice for the other. Each twin unit includes an upper water and steam drum I9 which extends the length of the setting from the front wall to the rear wall thereof. A water inlet pipe 2|] extends into the drum I9 through the front end thereof and rising from the top of the drum is a steam outlet 2|. The steam outlets 2l of the units A and B are connected by a manifold 22 from which a steam take-off pipe 23 leads (Figure 2).

A lower water drum 24 is mounted at the bottom of the compartment I'I and extends from a point adjacent the bridge wall I to and through the rear wall I2. The water drum 2f! is in vertical alinement with the upper drum I9. The upper and lower drums I9 and 24 of each of the steam generating units A and B are connected by a bank of boiler-circulating tubes 25 Which constitute the primary water heating elements. The outermost tubes of each vunit are designated 26 and extend vertically along the refractory side walls I3-I3 and act as Water wall cooling tubes. The tubes 25 are arranged inspaced transverse rows with the tubes of one row staggered relative to the tubes of the next adjacent row. The bank of tubes 25 substantially ll the gas flow compartment I'I, although a space 21a directly rearward of the bridge-wall I5 may be provided for the installation of superheater tubes (not shown). As the hot gases flow through the compartment I l, the tubes 25 forward of the intermediate baiiie I9b receive the more intense heat and those rearward of said baffle a lesser degree of heat. Therefore the rear rows of tubes 25 may be termed down-comers 25a and the forward rows may be termed up-comers 25h.

Referring to Figure 3 it will be noted that theV innermost of the tubes 25 of the units A and B are in alinement and these innermost tubes are designated 2'I. Alternate tubes 21 have their lower ends connected to the water drum 24 of unit A with the upper drum I9 of unit B, while the other tubes 21 have their lower ends connected to the lower drum 24 of unit B and their upper ends connected to the upper drum I9 of unit A. Thus the inner tubes 2l of the banks of tubes 25 interconnect the upper drum of one unit with the lower drum of the other unit and vice versa. This interconnecting of the tubes 21 and drums together, with a cross connection of the furnace wall tubes with the upper drums which will be hereafter described, function in a manner to maintain a common water level in the twinunit steam generator Ill and to produce certain other novel results as herein set forth.

Water wall tube headers 28--28 extend substantially the length of the side walls I3-l3 of the setting below the horizontal level of the lower drums 24--24. Water circulating tubes 29 connect the lower drums 24-24 with the respective headers 28-28, portions of said tubes 29 being en- (Iztsecllain an insulated section 30 of the side walls Forward of the bridge wall I5, the headers 28-28 are connected to the forward ends of the upper drums I9--I9 by right and left sets of furnace water wall tubes 3-I and 32 respectively. Each set of furnace water wall tubes is cross connected with the upper drums I9-i9 of the units A and B in a manner now to be described.

The tubes 3| and 32 rise upwardly from the headers 28-28 along the right and left side walls I3-I3 respectively of the furnace C. The drum I9 of the unit B being disposed at the right side of the setting D, alternate tubes 3l extend from the right header 2B directly to the upper drum I9 of unit B. The other alternate tubes 3l have their upper portions 33 bent inwardly to extend across the roof of the furnace and are connected to the inner side of the drum I9 of unit A. Likewise, alternate furnace water wall tubes 32 rise upwardly from the left header 28 along the left inner side wall I3 of the setting and directly connect with the upper drum I9 of unit A. The other alternate tubes 32 have their upper portions 34 bent inwardly to extend across the roof of the furnace and are connected to the inner side of the drum I9 of unit B. The alternate bent portions 33 and 34 of the furnace water wall tubes 3| and 3-2 cross midway of the furnace adjacent the roof thereof, and this feature together with the interconnecting of the primary boiler circulating tubes and upper drums of the units A and B serves to maintain a common water level within the steam generating units.

The refractory bridge wall I5 is cooled by water taken from the lower drums 24-24 and conveyed by water tubes to the upper drums I9-I9 of the units A and B. For cooling the bridge wall I5 I provide a transverse water header 55 which extends the width of the setting and which is disposed rearward of the bridge wall adjacent the bottom thereof. Each drum 24'is directly connected to the header 35 by tubes 36, the single header 35 being common to the tubes 36 of both units A and B. Extending from the front of the header 35 at spaced apart distances along the length thereof are two sets of bridge wall water cooling tubes 3'I which parallel the bridge wall and the tubes of the two sets have their upper ends respectively connected to the upper drums Iii-I9. Alternate tubes 31 extend along the front of the bridge wall while the other alternate ones have portions extending through the bridge wall as at 38 (Figures 1 and 2) and paralleling the rear side of the bridge wall.

In practice, assume that the twin steam generating units A and B are charged with water to the proper common level, and that the furnace C is being fired by the 'Stoker or by any other conventional firing methods. The heated gases evolved by combustion within the furnace or combustion chamber C, radiate heat to the side water wall cooling tubes 3| and 32 and to the crossing portions 33 and 34 thereof, the said portions forming the roof of the furnace, all of which induces effective steam generation in the secondary heating elements of the twin steam generating units A and B.

The gases from the furnace C pass therefrom through the passageway I E and into the gas flow compartment I'I and act upon the primary heating tubes 25 of the twin units A and B. The tubes 25 are arranged in rows, staggered with respect to the general direction of the gas flow from the furnace C to the gas outlet I 8. As the gases pass over, around and between the tubes 25 of the twin units on their way to the gas outlet I,` the direction of flow is reversed by the baiiies lila, I9b and I9c, causing cross iiow as well as parallel ow, thus obtaining better diffusion of the gases with resulting better heat absorption of the tubes 25 of the units A and B. The baflles cause the gas flow to travel in an undulant path from the furnace C to the gas outlet I8. The heated gases sweep the bottoms of the upper drums I9-I9 of the units A and B and the tops of the lower drums 24-24 thereof, and diminish in temperature as they travel toward the gas outlet I8. It is the heat transferred to the tubes 25 that causes water to rise in the forward upcomer groups 25D. The group of tubes 25h of the units A and B being subjected to the hottest gases, causes the generation of steam therein and a decrease in the density of the water, thereby inducing upward circulation.

The circulation of Water in the twin-unit steam generator after being heated in the aforesaid manner is forward through the headers 28-28, up through the secondary heating tubes 3|-32 to the upper drums IS-IB, upward through the front rows of primary tubes 25D to the upper drums I9-I9 and downward through the rear rows of tubes 25a to the lower drums 2li- 24, back to the headers 28-28 by way of the tubes 29-29. Alternate innermost tubes 21 of the primary tubes 25 of the units A and B connect the upper drum of one unit with the lower drum of the other unit which cross connection of the upper and lower drums of the units A and B acts to maintain a common water level in the circulatory systems of the twin units. The cross connection of the furnace water wall tubes 3 |-32 `with the upper drums |9--I9 also aids in maintaining a common water level in the upper drums of the twin units. The cross connection of the primary and secondary tubes with the upper drums of the twin generating units also serves to eiect a uniform generation of steam Which accumulates evenly in the upper drums i9-l9 and which steam is taken oi through the outlet pipe 23 which is connected Awith the two drums l9|9 by the manifold 22. The twin-unit generator IU produces in effect a double ring-flow circulation of water which is positive and rapid, which increases heat absorption, and Iwhich, by cross connection of the twin units, a uniform generation of steam is obtained and a common water level is maintained in the upper drums of the units.

While I have shown and described what I consider to be the preferred embodiment of my invention, I wish it to be understood that such ,1,

changes in design as come Within the scope of the appended claims may be resorted to without departing from the spirit of my invention.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A steam generator comprising a setting having a single compartment at the front thereof and a gas flow compartment at the rear thereof, a pair of upper water and steam drums extending side by side substantially the whole length of said setting including both compartments, a pair of lower water drums extending lengthwise rwithin said gas flow compartment only, one under each of the aforesaid drums, and two banks of primary heating tubes disposed side by side in said gas compartment and substantially lling same and directly connecting each upper drum to the lower drum beneath it, the innermost tubes at adjacent sides of said banks being alternately connected to one upper drum and the lower drum under the other upper drum, water wall tube headers within the setting and water tubes connecting said headers with the upper water and steam drums and the lowerwater drums of said generator.

2. A steam generator comprising a setting having a single furnace compartment at the front thereof and a gas flow compartment at the rear thereof, a pair of upper water and steam drums extending side by side substantially the whole length of said setting including both compartments, a pair of water drums extending lengthwise within said gas llow compartment only, one under each of the aforesaid drums, and two banks of primary heating tubes disposed side by side in said gas compartment and substantially filling same and directly connecting each upper drum to the lower drum beneath it, the innermost tubes at adjacent sides of said banks being alternately connected to one upper drum and the lower drum under the other upper drum, water wall tube headers within the setting, and vwater tubes connecting said headers with the upper water and steam drums and the lower water drums of said generator, the headers being arranged along the sides of the setting adjacent the bottom thereof and extending substantially the length thereof, said water tubes including separate sets each rising upwardly from one of the respective headers along the adjacent inner side of the furnace compartment, the upper drums being disposed one at each side of the longitudinal center of the setting, each set of water tubes directly connecting a header to the adjacent lower drum on the same side as said header, and the other tubes of said set extending transversely beneath the upper drum adjacent said side and being connected 1to the upper drum at the other side of the set- JOSEPH W. WALLIN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Date 

